Guidance system for hallux valgus correction

ABSTRACT

A guidance system comprises a first guide configured to be detachably mounted to a first portion of a bone. The first guide has a first axis for alignment with a longitudinal axis of the first portion of the bone. A second guide is mountable on the first guide. The second guide is slidably translatable in a transverse direction relative to the first axis. A third guide is mountable on the second guide. The third guide is selectively positionable along a curved path extending at least part way around the longitudinal axis.

FIELD

This disclosure relates generally to medical devices, and morespecifically to guidance systems for correcting bone deformities.

BACKGROUND

A bunion deformity (hallux valgus) is caused by a medial deviation ofthe first metatarsal and lateral deviation of the great toe (hallux).Distal osteotomies of the first metatarsal are commonly performed tocorrect hallux valgus. During the surgery, the surgeon cuts the firstmetatarsal along a plane that is transverse to the longitudinal axis ofthe first metatarsal, dividing the bone into a proximal portion(adjacent the medial cuneiform bone) and a distal portion (adjacent thefirst proximal phalanx). The distal portion is translated in the lateraldirection relative to the proximal portion, and the translated distalportion is fixed in place (using an implant and/or one or more fixationelements (e.g., screws, k-wires or rods). In some patients, in additionto the lateral deviation of the first metatarsal, the medial (tibial)and lateral (fibular) sesamoid bones of the first metatarsal aredisplaced. These sesamoid bones are embedded within the medial andlateral heads of the flexor halluces brevis tendons adjacent to theplantar surface of the first metatarsal. In the case of hallux valgus,the sesamoid bones may be displaced from the plantar side of the firstmetatarsal toward the lateral side of the first metatarsal.

SUMMARY

In some embodiments, a guidance system comprises a first guideconfigured to be detachably mounted to a first portion of a bone. Thefirst guide has a first axis for alignment with a longitudinal axis ofthe first portion of the bone. A second guide is mountable on the firstguide. The second guide is slidably translatable in a transversedirection relative to the first axis. A third guide is mountable on thesecond guide. The third guide is selectively positionable along a curvedpath extending at least part way around the longitudinal axis.

In some embodiments, a method for using a guidance system comprises:fixing a first guide to a bone; cutting the bone to provide a first boneportion and a second bone portion, the first bone portion having a firstlongitudinal axis; placing a second guide at a selected positionrelative to the first guide along a transverse direction normal to thefirst longitudinal axis; and moving a third guide around thelongitudinal axis to rotate the second portion of the bone to a targetangle relative to the first portion of the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of a first guide on a foot.

FIG. 1B is an enlarged detail of FIG. 1A.

FIG. 1C is a dorsal view of the foot with the first guide.

FIG. 2A is an isometric view of the foot and first guide, with a cutguide attached.

FIG. 2B is a dorsal view of the foot, first guide and cut guide of FIG.2A.

FIG. 3A is an isometric view of the first guide, a second guide, and athird guide on the foot.

FIG. 3B is a dorsal view of the first guide, second guide and thirdguide.

FIG. 3C is an isometric view of the second guide of FIG. 3A.

FIG. 3D is an isometric view of the third guide of FIG. 3A.

FIG. 4A is an isometric view showing the foot and guidance system aftertranslating the second guide along the first guide.

FIG. 4B is a dorsal view of the foot and guidance system aftertranslating the second guide along the first guide.

FIG. 5A is an isometric view showing the foot and guidance system afterrotating the third guide around the second guide and distal portion ofthe bone.

FIG. 5B is a dorsal view of the foot and guidance system after rotatingthe third guide around the second guide and distal portion of the bone.

FIG. 5C is an anterior view of the distal end of the first metatarsal,before rotation (in solid lines) and after rotation (in phantom).

FIG. 6A shows the guidance system with the fourth guide attached to thefirst guide.

FIG. 6B is a dorsal view of the guidance system with a variation of thefourth guide attached to the first guide.

FIG. 6C is a cross-sectional view of the guidance system taken alongsection line 6C-6C of FIG. 6B.

FIGS. 7A-7C are isometric, dorsal and medial views of the guidancesystem with a fixation device penetrating the fourth guide, proximalportion, and distal portion of first metatarsal.

FIG. 8 is a flow chart of a method of using the guidance system.

DETAILED DESCRIPTION

This description of the exemplary embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. In the description, relativeterms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,”“below,” “up,” “down,” “top” and “bottom” as well as derivative thereof(e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should beconstrued to refer to the orientation as then described or as shown inthe drawing under discussion. These relative terms are for convenienceof description and do not require that the apparatus be constructed oroperated in a particular orientation. Terms concerning attachments,coupling and the like, such as “connected” and “interconnected,” referto a relationship wherein structures are secured or attached to oneanother either directly or indirectly through intervening structures, aswell as both movable or rigid attachments or relationships, unlessexpressly described otherwise.

In the examples described below, the guidance system is used for acorrective surgery for hallux valgus. The examples herein refer tocorrection of the first metatarsal. In other embodiments—detaileddescription of which are omitted solely for brevity—the guidance systemis used for correction of deformities in other bones, where thecorrection can include a translation and/or a rotation of a secondportion of the bone with respect to a first portion of the bone.

This disclosure provides a guidance system for use during hallux valguscorrective surgery. The guidance system allows the surgeon to translatethe distal portion of the first metatarsal in the lateral direction androtate the distal portion about the longitudinal axis of the distalportion, to position the sesamoid bones in the proper (plantar)location.

Referring to FIG. 6A, in some embodiments, a guidance system comprises afirst guide 100 (FIG. 1A) configured to be detachably mounted to a first(proximal) portion 60 p of a bone 60. The first guide 100 has a firstaxis A for alignment with a longitudinal axis B of the first portion 60p of the bone 60. The first guide 100 can be fixed to the firstmetatarsal 60 using one or more fixation elements (e.g., k-wires,screws, rods, straps, clamps or the like) to provide reference surfacesfor a second guide 300.

The second guide 300 is mountable on the first guide 100. The secondguide 300 is slidably translatable in a transverse direction relative tothe first axis A, to translate the distal portion 60 d of the bone 60relative to the proximal portion 60 p.

A third guide 400 is mountable on the second guide 300. The third guide400 is selectively positionable along a curved path extending at leastpart way around the longitudinal axis B of the distal portion 60 d ofthe bone 60. In some embodiments, the third guide 400 is slidablymounted on the second guide 300, and the third guide 400 is pinned tothe distal portion 60 d of the bone 60. Sliding the third guide 400along the curved path results in rotation of the distal portion 60 d ofthe bone 60 about the longitudinal axis B of the distal portion 60 d.

Some embodiments further comprise a fourth guide 500 attachable to thefirst guide 100. The fourth guide 500 defines an aperture 522 (FIG. 6A)or slot 524 (FIG. 6C) for receiving a fixation element 550 aligned withthe second portion 60 d of the bone 60. For example, a k-wire, olivewire, or nail 550 can be passed through the aperture 522 and can enterthe proximal portion 60 p and distal portion 60 d of the bone 60.

Some embodiments further comprise a cut guide 200 (FIG. 2A) attachableto the first guide 100. The cut guide 200 has a slot 210 for receiving acutting tool (not shown), such as a burr or blade, for separating thesecond (distal) portion 60 d of the bone 60 from the first (proximal)portion 60 p of the bone 60.

Details of the guidance system components and their use are describedbelow.

FIGS. 1A-1C show the alignment and fixation of the first guide 100 onthe foot 50 of a patient. The first guide 100 is configured to bedetachably mounted to a first portion 60 p of a bone 60, such as thefirst metatarsal or other long bone. The first guide 100 has a firstmember 110 with a first axis A for alignment with a longitudinal axis Bof the bone 60. The first member 110 has a plurality of alignmentapertures 140 extending through the first member 110, from a proximalface to a distal face (where the proximal face is adjacent to the dorsalsurface of the foot). The alignment apertures 140 are configured toreceive fixation elements 130 (e.g., k-wires, olive wires, screws, orthe like). Although the exemplary first member 110 has five apertures140, other embodiments can include any desired number of apertures.

The first guide 100 has a second member 120, which can be perpendicularto the first member 110. The second member 120 has a first planarsurface 150 perpendicular to the first axis A of the first member 110.For example, the first guide 100 can be a T-shaped structure having avertical (first) member 110 containing the apertures 140 for receivingfixation elements 130 and a horizontal (second) member 120 having aplanar surface, rail or channel 170. As shown in the detail of FIG. 1B,the surface, rail or channel 170 can be a dovetail channel 170 or avertical-walled (right angle) channel facing away from the dorsalsurface of the foot 50. The horizontal member 120 of the first guide 100has a transverse edge 150 configured to face away from the proximalportion 60 p of the bone 60.

The transverse edge 150 lies along a plane that is orthogonal to thelongitudinal axis A of the vertical portion 110. of the first (proximal)portion 60 p of the bone 60. In some embodiments, the transverse edge150 has two mounting holes 160 (FIG. 1A) to receive correspondingalignment pins (not shown in FIG. 1A) of the cut guide 200 (FIGS. 2A and2B).

The surgeon can fix the first guide 100 to the first metatarsal 60 usingtwo of the fixation elements 130 in two of the alignment apertures 140.The surgeon can select two of the alignment apertures 140 based on localbone quality to ensure reliable positioning. The first guide 100 ispositioned along the length of the bone 60 so that the distance betweenthe transverse edge 150 and the distal end of the bone 60 is largeenough to accommodate the second guide 300 and the third guide 400.Additionally, the first guide 100 is positioned along the length of thebone 60 so that the distance between the transverse edge 150 and thedistal end of the bone 60 is at least large enough to accommodate thecut guide 200. In some embodiments (not shown), the second member 120has a positioning groove or protuberance (not shown), which the surgeoncan align (under fluoroscopy) with the first tarsometatarsal (TMT)joint. Two fixation elements 130 are inserted through the alignmentapertures 140.

FIGS. 2A and 2B show the cut guide 200 joined to the first guide 100. Insome embodiments, the cut guide 200 has two alignment pins (not shown)configured to fit snugly into the two mounting holes 160. In otherembodiments, the first guide 100 has pins (not shown) protruding fromthe transverse edge 150, and the cut guide 200 has corresponding holes(not shown) positioned to receive the pins. In other embodiments, one ofthe transverse edge 150 or the cut guide 200 has a channel or rail, andthe other one of the transverse edge 150 or the cut guide 200 has amating rail or channel. The cut guide 200 has a slot 210 having a width212 wide enough to receive a cutting tool (e.g., a burr or blade, notshown). The slot 210 can be longer than a diameter of the bone 60 to becut. In some embodiments, the cut guide 200 has a curved shapesubtending an arc angle θ. In some embodiments, the surgeon selects thecut guide from a plurality of cut guides having different cut angles,allowing the surgeon to select a chevron or transverse osteotomy.

With the cut guide 200 attached to the first guide, the surgeon caninsert a cutting tool (e.g., a burr or a blade, not shown) into the slot210 of the cut guide 200 and sweep the cutting tool through the bone toform a cut 62. Thus, the cut 62 separates the bone 60 into a proximalportion 60 p and a distal portion 60 d, as shown in FIG. 2B. Once thecut 62 is completed, the cut guide 200 is removed from the first guide100. The surgeon can hold the distal portion 60 d of the bone 60 inposition by hand at this time.

FIGS. 3A and 3B show the second guide 300 and the third guide 400attached to the first guide 100. FIG. 3C shows the second guide 300. Thesecond guide 300 has a mount 335, which can include a screw-receivinghole 340. A set screw or ball plunger 330 (FIG. 3A) locks the secondguide 300 in a desired medial-lateral position relative to the firstguide 100. The mount 335 of the second guide 300 is configured with achannel or rail (not shown in FIG. 3C) on its plantar side complementaryto the rail or channel 170 of the first guide. When the channel or railof the second guide 200 engages the rail or channel 170 of the firstguide, a second planar surface (proximal edge) 310 of the second guide300 abuts the first planar surface (distal surface) 150 of the firstguide 100. The second planar surface (proximal edge) 310 of second guide300 is arranged to slide in the transverse direction relative to thefirst planar surface 150 of first guide 100. The second guide 300 alsohas a surface 325 which can engage and guide an abutting edge 425 (FIG.3D) on the third guide 400.

The second guide 300 also has at least one slot or hole 320 forreceiving a locking member 420 (FIG. 3A) for locking the position of thethird guide 400 relative to the second guide 300. The locking member 420can be a set screw, a screw, a bolt, a ball plunger, or the like. Insome embodiments, the locking member 420 locks the third guide 400 inposition on the second guide 300, without contacting the bone 60.

The exemplary second guide 300 has a curved plate 315 with a curvedsurface defining the slot 320. When the mount 335 of the second guide300 engages the rail or channel 170 of the first guide 100, the curvedplate 315 wraps part way around the bone 60.

FIG. 3D shows the third guide 400. The third guide 400 is configured tobe slidably mounted on the second guide 300, so the third guide 400 canmove through a path that tracks the curvature of the second guide 300.Thus, when the third guide 400 slides (or revolves) relative to thesecond guide 300, the third guide follows a curved (e.g., circular,elliptical, or parabolic) path around the bone 60. In some embodiments,the second guide 300 and third guide 400 are both circular, and thethird guide 400 has a larger radius of curvature than the second guide300, for moving in a tangential direction within a cylindrical polarcoordinate system.

The third guide 400 has at least one slot or hole 410 for receiving thelocking member 420 (FIG. 3A) for locking the position of the third guide400 relative to the second guide 300. In some embodiments, the secondguide 300 has at least one round hole for fixedly locating the lockingmember 420, and the third guide 400 moves relative to the locking member420. In other embodiments, the second guide 300 has plural round holesor a slot for adjustably locating the locking member 420, and the thirdguide 400 moves relative to the adjusted location of the locking member420.

The third guide 400 can have additional surfaces and/or edges forengaging the second guide 300 and aligning the third guide 400 with thesecond guide 300. For example, the abutting edge 425 of the third guide400 slidably abuts the surface 325 of the second guide 300. Also, thethird guide 400 has a ridge 445 with a surface (not shown) that engagesthe edge 345 of the second guide.

The third guide 400 has at least one aperture 430 for receiving fixationmembers 440, such as k-wires, olive wires, rods or screws. The fixationmembers 440 pass through the apertures 430 of the third guide 400 andenter the bone 60. In some embodiments, the apertures 430 can beoriented toward the center of curvature of the plate 415.

For example, as shown in FIG. 3D, the third guide 400 can have a crosssection with a constant radius of curvature, with the apertures 430oriented so the fixation elements 440 passing through the apertures 430lie along radial lines a₁, a₂, and a₃ which converge at a point alongthe longitudinal axis B of the bone 60. In this configuration, when thethird guide 400 slides (or revolves) relative to the second guide 300,the third guide 400 moves in a tangential direction and traces an arc ofa circle having its center point at the center of the bone 60. In someembodiments, the slot 410 of third guide 400 subtends a sufficient angleto trace through an arc of 45 degrees. In other embodiments, the slot410 of third guide 400 subtends a sufficient angle to trace through anarc of 60 degrees. In other embodiments, the third guide 400 and itsslot 410 can be configured to subtend other arcs (e.g., 90 degrees).Relative to the lock 420, the third guide 400 can be adjusted by anyangle from zero to the angle of the arc subtended by the plate 415.

In preparation for surgery, the third guide 400 is preassembled to thesecond guide 300 and the locking member 420 is tightened. The thirdguide 400 is positioned relative to the locking member 420 to allow thethird guide 400 to slide (or revolve) over the second guide 300 andsubtend a sufficient angle of rotation to rotate the sesamoid bones tothe plantar position. For example, if the sesamoid bones are displacedby 45 degrees from the plantar position (towards the lateral side), thethird guide 400 is positioned with the end of slot 410 far enough fromthe locking member 420 to allow at least a 45 degree rotation of thedistal portion 60 d of bone 60 to reposition the sesamoids in theplantar position. The lock 420 is used to lock the third guide 400relative to the second guide 300. For example, if the lock 420 is ascrew, the screw 420 is tightened.

The rail (not shown) on the mount 335 of the second guide 200 isinserted in the channel 170 of the first guide 100. The (second andthird guide) subassembly 300, 400 is translated laterally along thechannel 170, so that the plate 415 of the third guide 400 isapproximately concentric with the bone 60. That is, the subassembly(second guide 300 and third guide 400) is positioned so the center ofcurvature of the third guide 400 coincides with the central longitudinalaxis B of the distal portion 60 d of bone 60. The surgeon can adjust theposition of the third guide 400 relative to the second guide 300, ifappropriate, to allow a desired range of adjustment of the third guide400. When the subassembly 300, 400 is in this concentric position, thesurgeon uses the set screw or ball plunger 330 (FIG. 3A) to lock thesecond guide 300 in a desired medial-lateral position relative to thefirst guide 100.

Fixation elements (e.g., k-wires) 440 are inserted through at least oneof the apertures 430 of the third guide 400 and into the distal portion60 d of the bone 60. In FIG. 3A, two fixation elements (e.g., k-wires)440 are inserted, for example. With the third guide 400 positioned sothe center of curvature of the third guide 400 coincides with thecentral longitudinal axis B of the bone 60, the apertures 430 align thefixation elements 440 with radial lines emanating from the centrallongitudinal axis B of the bone 60.

FIGS. 4A and 4B show the translation of the distal portion 60 d of thebone 60 in the lateral direction, relative to the proximal portion 60 p.Once the fixation elements 440 are inserted in the distal portion 60 dof bone 60, the set screw or ball plunger 330 is backed off sufficientlyto allow the mount 335 to slide along the rail or channel 170 of thefirst guide 100. The surgeon translates the distal portion 60 d of thebone 60 laterally by a sufficient offset to correct the medial deviationof the bone 60. When the desired lateral offset is achieved, the surgeontightens the set screw or ball plunger 330 to lock in the lateraloffset.

FIGS. 5A-5C show the axial rotation correction of the distal portion 60d of the bone 60. With the set screw or plunger 330 locking the secondguide 300 in position, the lock (e.g., threaded post or a spring loadeddevice) 420 is loosened to allow the third guide 400 to slide (orrevolve) in a curved path over the second guide 300. Thus, the thirdguide 400 subtends an arc around the longitudinal center of the distalportion 60 d of the bone 60, rotating the distal portion 60 d about itsaxis B. As best seen in FIG. 5C, the distal portion 60 d is rotatedabout its axis without translation. As shown in solid lines in FIG. 5C,the deviation of the bone 60 causes the sesamoids 61, 62 to deviatetowards the lateral direction. By moving the third guide 400 through itscurved path over the second guide 300, the distal portion 60 d isrotated until the sesamoids 61, 62 face in the plantar direction, asshown in phantom. When the desired rotation is achieved (and thesesamoids 61, 62 face the plantar direction), the lock 420 is againtightened to lock the third guide 400 relative to the second guide 300,and fix the relative rotation of bone portions 60 p, 60 d.

FIGS. 6A and 6B show attachment of the fourth guide 500 to the firstguide 100. FIG. 6C is a cross sectional view of the fourth guide 500,taken along section line 6C-6C in FIG. 6B. FIG. 6A shows a fourth guide500 having an enclosed cylindrical aperture 522, and FIGS. 6B and 6Cshow a fourth guide 500′ having a slot 524.

The fourth guide 500/500′ attaches to the first guide 100. A fastener512 is inserted through the fourth guide 500/500′ and into one of theapertures 140 of the first guide 100. The fourth guide 500 has a medialextension portion 520.

The medial extension portion 520 of fourth guide 500 (FIG. 6A) definesan aperture 522 for receiving a fixation element 550 aligned with thefirst portion 60 p and second portion 60 d of the bone 60 after applyingthe corrective translation and rotation to the distal portion 60 d. Forexample, a k-wire or nail 550 can be passed through the aperture 522 andcan enter the proximal portion 60 p and distal portion 60 d of the bone60. In some embodiments, as shown in FIG. 6A, the aperture 522 is acylindrical hole with anterior and posterior entrances, and the fixationelement (e.g., k-wire, olive wire, or the like) 550 is fed through theaperture 522, through the first portion 60 p of the bone 60, and intothe second portion 60 d of the bone.

In other embodiments (as shown in FIG. 6C), the medial extension portion520 of fourth guide 500′ has a slot 524 for receiving the fixationelement 550. The slot 524 extends from the lateral surface of the medialextension portion 522 to the interior (e.g., center) of the medialextension portion 522. The slot 524 is configured to permit quickremoval of the fourth guide 500′ from the first guide 100 and thefixation element 550, after the fixation element 550 is inserted throughthe first portion 60 p of the bone 60 and into the second portion 60 dof the bone.

FIGS. 7A-7C show the configuration of the guidance system after thefixation element 550 has been inserted through the aperture 522 of thefourth guide 500 (or slot 524 of fourth guide 500′), through the firstportion 60 p of the bone 60, and into the second portion 60 d of thebone. The fixation element 550 fixes the distal portion 60 d in abuttingrelationship with the proximal portion 60 p during the recovery fromsurgery.

Subsequently, to remove the fourth guide 500, the fastener 512 isremoved. In the case of the medial extension portion 520 having anenclosed cylindrical aperture 522, the fourth guide 500 (of FIG. 6A)slides in the posterior direction over the fixation element 550.

In the case of the fourth guide 500′ (FIG. 6C) having a slot 524extending to the lateral surface of the medial extension portion 520,once the fastener 512 is removed, the fourth guide 500′ can slide off ofthe fixation element 550 in the transverse (e.g., medial) direction,perpendicular to the axis of the fixation element 550. The slot 524 mayallow the surgeon to remove the fourth guide 500′ more quickly.

Once the fourth guide 500/500′ is removed, the surgeon can put acannulated drill over fixation element 550, insert a screw or nail inthe proximal portion 60 p and distal portion 60 d of the bone.

In some embodiments, the first guide 100, second guide 300, third guide400 and fourth guide 500/500′ comprise a radiolucent material (e.g.,polymer or aluminum), to allow the surgeon to insert and view a k-wireunder fluoroscope from the dorsal side of the guidance system.

FIG. 8 is a flow chart of an exemplary method of using the guidancesystem described above.

At step 800, the surgeon fixes the first guide 100 to the bone 60 (e.g.,first metatarsal), so that the proximal portion 110 of the first guideis aligned with the central longitudinal axis of the bone.

At step 802, the surgeon attaches the cut guide 200 to the first guide100. The attachment can be performed using pins and mating receptacles,a dovetail joint, or the like.

At step 804, the surgeon performs the osteotomy. For example, thesurgeon can insert a burr in the slot 210 of the cut guide 200 and sweepthe burr across the bone.

At step 806, the surgeon removes the cut guide 200 from the first guide100.

At step 808, the surgeon attaches the subassembly comprising the secondguide 300 and the third guide 400 to the first guide. For example, ifthe second guide has a rail and the first guide has a channel 170, therail is inserted in the channel and translated along the length of thechannel.

At step 810, the surgeon drives one or more fixation devices 440 (e.g.,k-wire or olive wire) through apertures 430 in the third guide and intothe distal portion 60 d of the bone. The apertures 430 can align thefixation devices 440 along respective radii emanating from the center ofcurvature of the third guide 400.

At step 812, the surgeon translates the second guide (relative to thefirst guide) so the rail (not shown) moves within the channel 170, tocorrect the medial deviation of the bone.

At step 814, the surgeon locks the second guide relative to the firstguide.

At step 816, the surgeon slides the third guide 400 over the secondguide 300 in the tangential direction, causing the third guide torevolve around the central axis of the distal portion 60 d of the bone60, and rotating the distal portion 60 d. The surgeon views the bone andguidance system by fluoroscopy, and determines that the rotationaldeviation of the bone is corrected when the sesamoids 61, 62 are in theplantar position. For example, if the surgeon is looking at a dorsalview, the sesamoids 61, 62 appear on the lateral side of the metatarsalbefore correction, and disappear from the dorsal view of the metatarsalwhen the rotation has been corrected.

At step 818, the surgeon locks the rotation of the third guide 400relative to the second guide 300.

At step 820, the surgeon attaches the fourth guide 500 or 500′ to thefirst guide 100.

At step 822, the surgeon inserts a fixation device (e.g., k-wire 550 orolive wire) through the aperture 522 of the fourth guide 500 (or theslot 524 of fourth guide 500′), the proximal portion 60 p of the bone,and into the distal portion 60 d of the bone.

At step 824, the surgeon removes the fourth guide 500/500′ from thefirst guide 100. For example, if the fourth guide 500′ is used, thesurgeon can slide the fourth guide 500′ off in the medial direction, sothe wire 550 exits the fourth guide via the slot 524. Once the fourthguide 500′ has been removed, the surgeon can insert a cannulated drillaround the fixation device 550, enlarge the opening in the proximalportion 60 p and distal portion 60 d, and insert a screw or nail intothe opening. Subsequently, after healing is completed, the fixationdevice 550, first guide 100, second guide 300 and third guide 400 can beremoved. In other embodiments, the surgeon may remove the first guide100, second guide 300 and third guide 400 prior to removal of thefixation device 550.

Although the subject matter has been described in terms of exemplaryembodiments, it is not limited thereto. Rather, the appended claimsshould be construed broadly, to include other variants and embodiments,which may be made by those skilled in the art.

What is claimed is:
 1. A guidance system, comprising: a first guideconfigured to be detachably mounted to a first portion of a bone, thefirst guide having a first axis for alignment with a longitudinal axisof the first portion of the bone; a second guide mountable on the firstguide, the second guide slidably translatable in a transverse directionrelative to the first axis; and a third guide mountable on the secondguide, the third guide being selectively positionable along a curvedpath extending at least part way around the longitudinal axis.
 2. Theguidance system of claim 1, wherein the third guide has a lock forfixing a position of the third guide along the curved path.
 3. Theguidance system of claim 2, wherein the lock comprises a threaded postor a spring loaded device.
 4. The guidance system of claim 1, furtherwherein the second and third guides include plates configured to receivethe threaded post extending through respective slots in the second andthird guides.
 5. The guidance system of claim 4, wherein the plates ofthe second and third guides further define at least one aperture forreceiving a fixation element therethrough.
 6. The guidance system ofclaim 4, wherein the plate of the third guide is curved.
 7. The guidancesystem of claim 1, wherein the first guide has a first planar surfaceperpendicular to the first axis, and the second guide has a secondplanar surface arranged to slide in the transverse direction relative tothe first planar surface.
 8. The guidance system of claim 1, furthercomprising a fourth guide attachable to the first guide, the fourthguide defining an aperture for receiving a fixation element aligned withthe second portion of the bone.
 9. The guidance system of claim 8,wherein the fourth guide has a slot continuous with the aperture of thefourth guide, configured for removal of the fourth guide from the firstguide and the fixation element, while the fixation element is insertedin the second portion of the bone.
 10. The guidance system of claim 1,further comprising a cut guide attachable to the first guide, the cutguide having a slot for receiving a cutting tool for separating a secondportion of the bone from the first portion of the bone.
 11. The guidancesystem of claim 1, wherein: the first guide is a T-shaped member havingapertures for receiving fixation elements and a planar surface, rail orchannel for guiding the second guide; the second guide includes a plateconfigured to move in a tangential direction along the surface, rail orchannel; and the third guide is a curved plate having a slottherethrough, the guidance system further comprising a threaded post ora spring loaded device extending through the slot of the third guide,for locking the third guide relative to the second guide.
 12. A methodfor using a guidance system, comprising: fixing a first guide to a bone;cutting the bone to provide a first bone portion and a second boneportion, the first bone portion having a first longitudinal axis;placing a second guide at a selected position relative to the firstguide along a transverse direction normal to the first longitudinalaxis; and moving a third guide around the longitudinal axis to rotatethe second portion of the bone to a target angle relative to the firstportion of the bone.
 13. The method of claim 12, wherein the third guideincludes a plate defining a slot therein, and the moving step includessliding the third guide relative to a post extending through the slot.14. The method of claim 13, further comprising inserting at least onefixation device through an aperture in the third guide and into thesecond portion of the bone.
 15. The method of claim 12, wherein theplacing step includes sliding the second guide along a transverse edgeof the first guide, and locking the second guide to the first guide. 16.The method of claim 12, further comprising: attaching a fourth guide tothe first guide; inserting a fixation device through the fourth guideand into the first and second portions of the bone in a direction havinga longitudinal component, the longitudinal component parallel to asecond longitudinal axis of the second bone portion.
 17. The method ofclaim 16, further comprising removing the fourth guide by moving thefourth guide in a transverse direction relative to a third longitudinalaxis of the fixation device.
 18. The method of claim 16, wherein thefixation device is a rod or wire, the fourth guide has a longitudinalslot through which the fixation device extends, the inserting stepinserts the fixation device through the longitudinal slot, the methodfurther comprising moving the fourth guide so the fixation device passesout through the longitudinal slot in a direction transverse to thesecond longitudinal axis of the second bone portion.
 19. The method ofclaim 12, wherein the cutting step includes attaching a cut guide to thefirst guide, and cutting the bone through the cut guide.